Radikal Therapeutics (RTX) has invented a novel first-in-class bifunctional nitric oxide (NO) donor and redox catalyst (R-190) to treat septic shoc. In rodent and ovine models of endotoxemia and gram negative bacillary septic shock, therapeutic resuscitation with R-190 improves outcome across clinically-relevant endpoints, including hemodynamics, oxygenation, and end-organ injury. In an LD100 murine model of endotoxemia, post-LPS administration of R-100 or R-190 dose-dependently blocked renal, lung, and hepatic injury 73-90%, inhibited histologic damage in liver, kidney, lung, and gut by 75-90%, and assured 100% survival. In an ovine model of Pseudomonal septic shock, R-190 resuscitation restored hemodynamics and oxygenation. The proposed scope of work will construct a PD profile in a clinically-relevant septic shock model, design and implement methods to release and track the active pharmaceutical ingredient, and develop bioanalytical methods of R-190 and its metabolites. Aim #1: Establish the pharmacodynamic (PD) profile of R-190 in an ovine model of sepsis RTX will carry out a placebo-controlled randomized study wherein septic shock is produced in an LD100 model in mechanically-ventilated male Merino sheep administered an inoculum of Pseudomonas aeruginosa via an IV route. We will carry out studies in order to establish the dose-response, time-window, and safety of R-190 in the septic sheep. Task #1: R-190 (30, 100, and 300 mg/kg IV q6h IV) will be compared to vehicle control wherein the initial dose is delivered 1 h post onset of bacteremia, in order to establish the lowes dose providing optimal outcome (LDPOO). Plasma levels of R-190 will be measured q6h, to relate drug concentration to efficacy. Task #2: We will determine the duration of the therapeutic time window by initiating R-190 therapy 1, 2, 4, 8, 12, or 24 h (at the LDPOO dose) after the onset of bacteremia. Hemodynamic, oxygenation, and ventilatory parameters will be assessed q3h. Serum and tissue will be examined 48 h post onset of bacteremia for determination of response to R-190. Aim #2: Synthesize R-190. Develop analytical methods for release and stability. Define impurities and degradants and thereby define optimal storage conditions and dosing formulation. R-190 API material will be qualified prior to use in the ovine studies in order to assure identity and purity. Analytical methods will be developed following ICH guidelines for this purpose and to establish storage conditions and stability of the R-190 API and dosing solutions. Aim #3: Develop a bioanalytical methodology to quantitate R-190 and its metabolites in plasma RTX will construct a pharmacodynamic profile relating plasma concentrations of R-190 and its metabolites to pharmacologic activity. A robust bioanalytical LC-MS/MS approach will be developed with an LOQ 2 logs less than existing methods, allowing for identification and quantitation of plasma R-190 and its major metabolites at the low ng/mL level. We will qualify this approach for linearity, precision, and accuracy, and define the conditions of plasma preparation and storage that optimize reliability of this methodology.